The difficulty of homogeneously mixing a comminuted dried material into a mass of another comminuted dried material, especially when it is necessary to process large quantities of dry materials is time consuming and cumbersome. An operation of this kind is usually performed manually by a batch process and is tedious. The mixing must normally be scheduled well in advance to be ready for use when needed and frequently results in delaying an operation that would otherwise be a relatively expeditious procedure if a capability were available to perform the blending in a continuous manner. One situation of this kind, for example, involves the introduction of a powdered lubricant into the body of a mass of material that is to fed to and shaped in a mold or press. One particular operation of this kind involves adding a lubricant to a powdered or granulated chlorine chemical which is to be formed into tablets in a tablet forming press. In the tablet forming press, unless the lubricant is substantially uniformly mixed with the material to be formed in the mold press, the sticking of the material to the mold may result in an imperfect shape and often results in a serious interruption in the tablet forming production.
While efforts have been made in certain tablet forming or other molding operation to introduce a liquid lubricant into the shaping press, such as by the means disclosed in U.S. Pat. No. 3,483,594, this approach is limited in applicability to materials that can be processed by this means and is not suitable, and in some cases cannot be tolerated, in other environments. For example, in the manufacture of chlorine containing tablets obtained by forming the tablets in a mold or press, the use of a liquid lubricant is entirely unsuitable. The system as a practical matter must be maintained dry. It is necessary that a solid lubricant be blended into the dry chlorine powder which is to be shaped into tablets. This blending in of the solid lubricant, as a practical matter, has been heretofore carried out by the hand addition of the dry lubricant to the chlorine powder at a considerable cost in time and manpower. The need for a practical and efficient alternative to such manual intermixing of two finely divided solids is apparent.